共查询到15条相似文献,搜索用时 125 毫秒
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刚性柱附近浅水爆炸时冲击波传播、气泡射流受多种因素影响。考虑水面、水底、刚性柱与水下爆炸冲击波及气泡的耦合作用,基于LS-DYNA有限元软件,建立浅水爆炸全耦合模型,通过经验公式验证有限元模型的正确性。研究表明:采用炸药直径1/3~1/2中心渐变网格能够较好地保证数值模拟精度。在冲击波传播阶段,刚性柱迎爆区冲击波峰值上升并产生切断现象,冲击波下降段被"截断",而背爆区冲击波峰值衰减约50%,同时正压作用时间增加;在气泡脉动阶段,气泡在收缩阶段产生指向刚性柱的气泡射流,当刚性柱与炸药之间的距离约为一个气泡半径时,刚性柱附近的脉冲荷载增幅最大,脉冲荷载最大测点水深较爆心上移。 相似文献
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为了系统地研究铝氧比对含铝炸药水下爆炸载荷及能量输出结构的影响,在验证数值模型有效性的基础上,针对铝氧比分别为0、0.16、0.36、0.63的RDX基含铝炸药,利用耦合欧拉-拉格朗日方法模拟了其水下爆炸连续的全过程,考虑了冲击波载荷和气泡载荷之间的耦合作用,从冲击波、气泡和能量输出结构三方面对影响效应进行评估。计算结果表明:随着铝氧比的增大,含铝炸药水下爆炸冲击波衰减时间常数、冲击波冲量、气泡脉动周期、气泡最大半径以及比气泡能都增大;铝氧比为0.36时,冲击波峰值压力、冲击波能流密度和比冲击波能达到最大。铝粉的加入对气泡能的提高相对于冲击波能更加显著。 相似文献
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由于在水下爆炸冲击波的数值仿真研究中,水的状态方程、人工黏性系数和网格尺寸对数值计算结果影响很大,采用常规TNT炸药的水下爆炸为例,以冲击波的峰值压力和比冲量为衡量指标,研究了这3个主要影响因素对数值仿真结果的影响。首先,通过采用常用的5种水的状态方程进行系列仿真,给出了各种状态方程的适用范围;其次,讨论了人工黏性系数对计算结果的影响,并给出了一次与二次人工黏性系数的建议取值范围;最后,通过对不同炸药当量及不同网格尺寸开展系列运算,从而得到不同炸药当量在满足工程计算精度要求下所对应的建议网格尺寸,并得到了不同炸药当量所对应的建议网格尺寸的表达式。 相似文献
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根据鱼雷对舰船毁伤的特点,建立了多介质水下爆炸数值模型,提出了交界面处理及广义光滑长度计算方法,编制了多介质水下爆炸计算程序,并对水下爆炸空气隔层衰减冲击波的性能进行了定量分析。结果表明:无论是接触爆炸还是非接触爆炸,空气隔层均可有效衰减冲击波,并且接触爆炸中空气隔层衰减冲击波的效果更好,最大可使冲击压力峰值降低约55%;空气隔层厚度与爆炸厚度之比为1时便可达到较好的衰减冲击波效果,继续增加空气隔层厚度对衰减冲击波效果影响不大。研究结果可为舰船结构防护及防雷舱的结构设计提供参考。 相似文献
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通过理论计算和水下爆炸实验,初步研究了MgH2敏化储氢型乳化炸药的爆炸特性和爆轰反应机理。结果表明:与玻璃微球敏化的乳化炸药相比,MgH2敏化的乳化炸药水下爆炸的冲击波超压、比冲量、比冲击波能、比气泡能及水下爆炸比总能量显著增加,其中冲击波超压和水下爆炸总能量分别增加了20.5%和31.0%。MgH2储氢型乳化炸药的爆轰机理与玻璃微球敏化乳化炸药不同,MgH2在乳化炸药中起到了敏化剂和含能材料的双重作用,即MgH2在乳化基质中水解产生均匀分布的氢气泡,起到了敏化作用,同时氢气参与爆炸反应,提高了炸药的爆炸能量和做功能力。 相似文献
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Aluminum(Al) powders are used in composite explosives as a typical reducing agent for improving explosion performance. To understand energy release of aluminum in aluminized RDX-based explosives, a series of thermal measurements and underwater explosion(UNDEX) experiments were conducted. Lithium fluoride(LiF) was added in RDX-based explosives, as a replacement of aluminum, and used in constant temperature calorimeter experiments and UNDEXs. The influence of aluminum powder on explosion heat(Qv) was measured. A rich supply of data about aluminum energy release rate was gained. There are other oxides(CO_2, CO, and H_2O) in detonation products besides alumina when the content of RDX is maintained at the same levels. Aluminum cannot fully combine with oxygen in the detonation products. To study the relationship between the explosive formulation and energy release, pressure and impulse signals in underwater experiments were recorded and analyzed after charges were initiated underwater. The shock wave energy(Esk), bubble energy(Eb), and total energy(Et) monotony increase with the Al/O ratio, while the growth rates of the shock wave energy,bubble energy, and total energy become slow. 相似文献
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Underwater explosions have found extensive application in technology, acoustics and physics. Most investigations using underwater explosions are performed as full-scale tests, this is mainly due to the widely held view that reliable measurements of pressure waves taken at a short range from the detonation of small amounts of chemical explosives are extremely difficult, if not impossible, to perform. On the basis of a number of tests where small amounts of explosives, ranging from 0.2 to 6 g were detonated, the scaling law for underwater explosion shock waves was generalized and includes short distances and very small charge weights typical of laboratory conditions. Empirical expressions for the peak pressure, time constant, impulse and energy flux density as a function of charge weight and distance have been worked out. Excellent agreement was found between the peak pressures calculated using the empirical expression and the corresponding values calculated using Kirkwood - Bethe's theory for underwater shock waves. Various scaling effects, which if not realized may lead to erroneous results, are emphasized. It is concluded that small scale (laboratory) underwater explosion tests, give valid useful results and may be used instead of traditional full scale tests in a number of fields. 相似文献